Promoting breastfeeding in women with gestational diabetes mellitus in high-income settings: an integrative review

Background Breastfeeding provides many short- and long-term health benefits for mothers and their infants and is a particularly relevant strategy for women who experience Gestational Diabetes Mellitus (GDM) during pregnancy. However, breastfeeding rates are generally lower amongst this group of women than the general population. This review’s objective is to identify the factors that influence breastfeeding by exploring the experiences and outcomes of women in in high-income health care contexts when there is a history of GDM in the corresponding pregnancy. Methods A comprehensive search strategy explored the electronic databases Medline, CINAHL, Web of Science and Scopus for primary studies exploring breastfeeding practices for papers published between January 2011 and June 2023. All papers were screened independently by two researchers with included papers assessed using the Crowe Critical Appraisal tool. Findings were analysed using a narrative synthesis framework. Results From an initial search result of 1037 papers, 16 papers representing five high-income nations were included in this review for analysis – the United States of America (n = 10), Australia (n = 3), Finland (n = 1), Norway (n = 1), and Israel (n = 1). Fifteen papers used a quantitative design, and one used a qualitative design. The total number of participants represented in the papers is 963,718 of which 812,052 had GDM and 151,666 did not. Women with an immediate history of GDM were as likely to initiate breastfeeding as those without it. However, they were more likely to have the first feed delayed, be offered supplementation, experience delayed lactogenesis II and or a perception of low supply. Women were less likely to exclusively breastfeed and more likely to completely wean earlier than the general population. Maternity care practices, maternal factors, family influences, and determinants of health were contextual and acted as either a facilitator or barrier for this group. Conclusion Breastfeeding education and support need to be tailored to recognise the individual needs and challenges of women with a history of GDM. Interventions, including the introduction of commercial milk formula (CMF) may have an even greater impact and needs to be very carefully considered. Supportive strategies should encompass the immediate and extended family who are major sources of influence. Supplementary Information The online version contains supplementary material available at 10.1186/s13006-023-00603-y.


Background
Gestational diabetes mellitus (GDM) is a common medical condition reported during pregnancy, particularly in high-income healthcare settings [1,2].It is defined as glucose intolerance that emerges or is first recognised during pregnancy [3][4][5].Unlike other types of diabetes, it is characterised by insulin resistance developed from placental hormonal release in which the maternal insulin response can no longer compensate for the insulin resistance, resulting in maternal hyperglycaemia [4].
The pooled standardised global prevalence of GDM is 14.0% with the highest prevalence of GDM across high-income nations [6].GDM rates have dramatically increased due to several factors, such as increasing rates of obesity and maternal age, predisposition to GDM through a family history of type 2 diabetes mellitus (T2DM), or an ethnicity predisposed to developing GDM [1,7,8].The increase has been further impacted by the introduction and wide global adoption of the World Health Organization (WHO) diagnostic guidelines in 2013, that have resulted in more women receiving a GDM diagnosis [1,3,9].
GDM increases the risk of adverse outcomes and longterm health complications for women and their infants [4,8,10].Women with GDM have increased risks of complications during pregnancy including pre-eclampsia, hypertension, higher rates of birth trauma and birth interventions [2,[11][12][13].Infants are also at increased risk of preterm birth, macrosomia, respiratory problems, and hypoglycaemia [14,15].Both women and their infants experience increased risks of longer-term impacts such as obesity and cardiometabolic disorders, with research revealing a tenfold increase in the risk of T2DM for mothers with a history of GDM [2,16,17], as well as a risk of women developing GDM in subsequent pregnancies [18].There is also an increased risk of developing renal, ophthalmic or cardiovascular diseases for women and their infants [13,15,16,19,20].The health care costs associated with GDM may also impact the health system.For example, in Australia, in 2019-20 GDM as a pregnancy episode was estimated to cost the health care system $63.6 million AUD, with hospital services accounting for 84% ($53.4 million AUD) [21].This cost does not account for the goods and services required to manage any longer-term adverse health outcomes.
Despite the issues associated with GDM, it is known that the comorbidities and risks can be significantly reduced or managed with health behaviour changes, such as diet and physical exercise alongside monitoring blood glucose levels (BGL) [11,22].Some women may also require pharmacological management, using insulin or oral hypoglycaemic medications [23].Optimal treatment during pregnancy reduces the incidence of GDM-related pregnancy complications including macrosomia and maternal hypertensive disorders [4].In addition to health behaviour changes and antenatal interventions, studies have shown the importance of breastfeeding in improving longer-term outcomes for women with GDM and their infants [24,25].Aside from the benefits of exclusive breastfeeding to six months of life [26], further evidence suggests that being breastfed for longer periods of time reduces infants' rates of obesity and diabetes in adulthood [27].This finding has even more significance for women with a history of GDM and their infants, in reducing the longer-term risks associated with this condition.
Despite the known public health benefits of breastfeeding following a pregnancy complicated by GDM, current literature identifies issues of concern for mother-infant dyads with this complexity.Research demonstrates that women with GDM experience unmet care needs within current models of care [28,29].This is also of concern with the growing number of women experiencing GDM [2,30].A recent study suggested there were maternal and infant biological factors, provider practices, breastfeeding experiences and support plus cognitive and social factors contributing to the disparity in breastfeeding rates between women with a history of GDM and their non GDM counterparts [31].A recent systematic review and meta-analysis also examined interventions for women with obesity and/or GDM to promote breastfeeding, finding that support increased initiation and duration for these women [32].However, no reviews were found that explored the factors that positively influence or hinder the promotion and support of breastfeeding in women with GDM, to address this unmet need.
The objective of this review is to identify the factors that influence breastfeeding, as well as to explore the experiences and outcomes of women in in high-income health care contexts when there is a history of GDM in the corresponding pregnancy.Our review is unique in that it focusses on women with a recent GDM diagnosis only and does not include women with Type 1 diabetes mellitus (T1DM) or Type 2 diabetes mellitus (T2DM).The amount and availability of human and fiscal resources within a country may impact GDM care and subsequent breastfeeding practices, which limits the generalisability of findings, particularly to the Australian context.Consequently, this review has focussed on findings from high income nations, as defined by the World Bank, and who are presumed to have comparable health spending and burden, to increase confidence [33].This review contributes to the field by integrating the best available evidence in the promotion of breastfeeding in women who have a recent history of GDM, to inform policy, practice and future research efforts.

Design
In addressing the objective of this review, studies relating to the breastfeeding experiences and outcomes of women with a recent history of GDM in high income healthcare settings, utilising quantitative, qualitative, or mixed methods methodology were included.We used Whittemore and Knafl's integrative review methodology to guide the process: problem identification, literature search, data evaluation and extraction, data analysis, and presentation of results [34].An integrative approach was taken to analysis and reporting whereby both quantitative and qualitative data are synthesised allowing for a comprehensive and holistic understanding of the topic.The research question guiding this review was: what are the breastfeeding experiences and outcomes of women when there is a history of GDM in the corresponding pregnancy?A research protocol was developed a-priori and published in the International Prospective Register of Systematic Reviews database (PROSPERO) (CRD42022292712).

Search strategy and procedures
A search strategy was developed with the support of a specialist librarian with expertise in systematic reviews.The SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research Type) framework was used to develop search terms [35] -see Table 1.The full search strategy is outlined in Supplementary Table 1.
The databases Web of Science, CINAHL, Scopus, and Medline were searched using the search terms.Searches were limited to publication date between January 2011 and June 2023 to reflect contemporary maternity care, and the filters 'English' language, and 'human' studies were applied where available.

Inclusion and exclusion criteria
The following inclusion and exclusion criteria were applied to studies for this review.Studies were included if they: (1) focused on women with a diagnosis of, and treatment for, GDM during a recent pregnancy (participants were less than 2 years or postpartum from a pregnancy affected by GDM); (2) focused on 'any' form of breastfeeding or breast milk feeding; (3) highlighted or explored influencing factors or barriers of GDM on the woman's breastfeeding experience; (4) used data collected from high-income nations -as defined by the World Bank [33]; (5) were published in the English language; and (6) were primary studies of a qualitative, quantitative or mixed methods design; and (7) were published in peer-reviewed journals from 2011 onwards.Studies were excluded if they did not meet all the inclusion criteria.Studies focussing on the antenatal, labour and birth rather than the postpartum period, or on women with T1DM or T2DM or other conditions associated with/or are present during pregnancy, were excluded.Additionally, studies that were not primary in nature such as reviews, abstracts, commentaries, editorials, or grey literature were excluded.The process was guided by the WHO operational definitions of breastfeeding [26].High-income nations were identified using the World Bank criteria, with 81 nations holding this status in 2023 [33].These nations have a Gross National Income (GNI) of $13,206 USD per capita or more and are associated with high-income healthcare.
The selection of final papers for analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flow chart as illustrated in Fig. 1 [36].Papers were reviewed and managed using Covidence -an online systematic review tool, that allows for the screening, extraction, and analysis of data [37].Following the search, all the identified citations were imported into Covidence.Duplicates were removed and the remaining papers were screened according to the inclusion and exclusion criteria [37].All stages of the screening process were conducted independently by two authors, with any conflicts resolved through team discussion.GO and MEH conducted the search with the support of the specialist librarian and uploaded all citations to Covidence.Three authors conducted reviews based on title and abstract (GO, EK and MA).The full texts of selected papers were retrieved and assessed in detail against the inclusion criteria by three of the authors (GO, EK and MA).

Quality assessment
The Crowe Critical Appraisal Tool (CCAT) v1.4 was utilised to critically appraise the full-text papers [38].This tool allows for the appraisal for a variety of research designs and is used to appraise the design, sampling, data collection and ethical practices of research papers, with higher scores indicating high quality, rigorous, minimally-biased research [38].There are eight domains in the CCAT, with details on the individual domains available in the CCAT User Guide [39].Each domain was scored between 0-5, with 0 being lowest possible score and 5 the highest.Each full-text paper was appraised independently by two authors (MA, GO, MEH or EK).

Data extraction and analysis
Data extraction and analysis was conducted by GO, MA and EK.Data from the included papers were manually extracted by two of the researchers, checked by a third and presented in tabular format to facilitate comparison and analysis across the studies -see Table 3.This table comprises data on the individual studies including the characteristics of the studies; positive and negative influences or factors to breastfeeding; and breastfeeding initiation and duration.Pooling of the data for meta-analysis was not conducted, given heterogeneity in the study designs, methods, and outcomes [40].When heterogeneity exists, a narrative synthesis is considered appropriate to synthesise the data [40].This approach allows for the findings to be integrated and allows for the exploration of similarities and differences among the studies [41].This review adopted the narrative synthesis approach outlined by Popay et al.: developing a theory; developing a preliminary synthesis; exploring relationships in the data; and assessing the robustness of the synthesis [42].The process of narrative synthesis was assisted with the use of NVivo Pro (version 12) software.In the process of data analysis, the findings of all papers were collated.Descriptive themes were constructed in a separate set of codes in NVivo and were discussed by the team and agreed on by consensus.

Results
Database searches produced a total of 1037 publications.After duplicates were removed, 539 papers were screened by title and abstract; 466 papers were removed as their content did not meet the inclusion criteria.The full text of the remaining 73 papers were assessed for eligibility with 57 excluded at this stage (see Supplementary Table 2 for a list of excluded papers).Sixteen papers were included for analysis.Each of the 16 papers were assessed utilising the CCAT.Scores from the two independent appraisals were discussed and compared by the research team, with the average score for each paper outlined in Table 2.The independent scoring of each domain is also outlined in Table 2, providing a granular and transparent overview of the appraisal process.The total scores across the sixteen papers ranged from 68.75% to 87.5%, indicating satisfactory quality, with no papers excluded based on the CCAT score.A total of sixteen papers were included in the review representing five high-income nations -the United States of America (n = 10), Australia (n = 3), Finland (n = 1), Norway (n = 1), and Israel (n = 1).The total number of participants represented in the papers is 963,718 of which 812,052 had a history of GDM and 151,666 did not.Fifteen papers used a quantitative design, and one used a qualitative design.The fifteen papers using a quantitative study design included: eleven cohort studies [43, 44, 46, 48, 49, 51-54, 56, 57]; two papers with both a cross-sectional and a cohort design [47,55]; one prospective case control study [45]; and one randomised control trial [58].Three papers used the US Infant Feeding Practices Study II data set [47,49,53] however, they reported on different aspects of it.Data collection methods varied between studies and included hospital records, birth registers, national statistics, and surveys.The single qualitative paper involved a phenomenological approach [50].A summary of data extracted from the included papers is found in Table 3.
The findings from this review have been integrated and are presented under four broad themes, constructed during the analysis.The four broad themes are: breastfeeding outcomes, maternity care practices, maternal factors and family influences, and underlying determinants of health, and these findings are outlined in Table 4.

Initiation
Cordero et al. found the most significant predictor of breastfeeding initiation was intention of breastfeeding [46].However, one study found women with a recent history of GDM were less likely to report breastfeeding in the first hour (aOR 0.83; 95% CI 0.73, 0.94); feeding on demand (0.86; 0.74, 0.99); and feeding only breast milk in the hospital (0.73; 0.65, 0.82) in comparison to women without GDM [57].Two papers reported similar findings.Loewenberg Weisband et al. found women with GDM were had a lower likelihood of intending to exclusively breastfeed than women without GDM (aOR 0.71; 95% CI 0.51, 0.99) [53].Similarly, Chamberlain et al. also reported that women with GDM were also less likely to exclusively breastfeed than women without GDM (OR 0.32; 95% CI 0.27, 0.38, P < 0.0001) [44].
Two studies found similar rates of breastfeeding initiation regardless of GDM status.Kachoria and Oza-Frank found predictors of breastfeeding initiation were mostly similar among mothers with GDM and those without [51].Whilst Baerug et al. found that 99% of all women initiated breastfeeding regardless of GDM status [43].However, after 12 weeks, only 56% of the mothers with GDM compared to 67% of the mothers without GDM predominantly breastfed (p = 0.02) [43].

Duration
Three studies reported that women with GDM were less likely to breastfeed on discharge.Haile et al. found that at hospital discharge, 62.2% among women with a recent history of GDM exclusively breastfed, compared to 75.4% of women without GDM (P < 0.01) [49].Longmore et al. similarly found that 75% (OR 0.7; 95% CI 0.4, 1.3) of women with GDM breastfed on discharge compared to 84% of women without GDM [54].Morrison et al. found that while 97% of women with a recent history of GDM had 'ever' breastfeed, only 19% had breastfed for 3 months (p = 0.001) [55].Two studies found there was no difference in the duration of breastfeeding when comparing women with GDM and those without GDM.Loewenberg Weisband et al. found that regardless of GDM, breastfeeding duration was similar when comparing exclusive breastfeeding intentions and by hospital supplementations [53].Laine et al. also reported no differences in the duration of breastfeeding when comparing women with GDM (7.5 months [SD 3.7]) and those without GDM (7.9 months [SD 3.7]) (p = 0.17) [52].
Across the papers there were variations in the findings in relation to initiation and duration of breastfeeding.Women with GDM may be just as likely to initiate breastfeeding as women without GDM, however, across the studies, it appeared women with GDM were more likely to report delays to breastfeeding in the first hour, were less likely to exclusively breastfeed or were more likely to cease breastfeeding than women without GDM.

Maternity care practices
Eight quantitative studies and the qualitative study reported on maternity care practices which influenced breastfeeding outcomes, these are largely birth interventions and complications, supplementation with CMF, and education and support [44, 46-48, 50, 55-58].with a history of GDM and women without a history of GDM (p = 0.17) • Mothers with a history of GDM: 7.5 (SD 3.7) months • Mothers without a history of GDM: 7.9 (SD 3.5) months á duration of breastfeeding for male infants born to mothers with a history of GDM compared to female infants born to mothers with a history of GDM (maternal age, pre-pregnancy body mass index, marital status, educational attainment, duration of pregnancy, and smoking habits adjusted p = 0.042) • Data only available on any breastfeeding, not separately on exclusively, predominant, and partial breastfeeding • Missing maternal data on women's dietary and physical activity habits, as well as gestational weight gain • All women were Finnish, therefore the generalisability of the study observations is limited  • Electronic medical records Among women with a history of GDM, the proportions of those exclusively breastfeeding at hospital discharge was similar among both Indigenous and non-Indigenous Australian women • Indigenous women: 77% • Non-Indigenous women: 75% á likelihood of Indigenous Australian women with a history of GDM to be predominantly breastfeeding at 6 weeks postpartum, compared to non-Indigenous Australian women with a history of GDM.(p < 0.001) • Indigenous women: 81% • Non-Indigenous women: 57% á likelihood of Indigenous Australian women with a history of GDM to be predominantly breastfeeding at 6 months postpartum, compared to non-Indigenous women with a history of GDM.(p < 0.001) • Indigenous women: 68% • Non-Indigenous women: 46% Indigenous and non-Indigenous Australian women with a history of GDM were as likely to achieve predominant breastfeeding or exclusive breastfeeding at 6 weeks or 6 months as women without a history of GDM  and infant feeding data • Self-administered questionnaire Women with a history of GDM initiated any breastfeeding as often as women without a history of GDM á likelihood of women with a history of GDM reporting the introduction of formula milk within the first 2 days of life, compared to women without a history of GDM (aOR 3.48; 95% CI, 1.47-8.26) • Women with a history of GDM: 79.4% • Women without a history of GDM: 53.8%, Women with a history of GDM initiated pumping 4 days earlier than women without a history of GDM (P < 0.05) No difference in the proportion of women reporting breastfeeding difficulty when comparing women with and without a history of GDM OR 2.08; 95% CI, 0.78-5.52 • The subset of women with GDM in this sample is small and results may not be generalisable to all women with GDM history

Birth interventions and complications
Birth interventions and complications after a pregnancy affected by GDM were associated with an increased risk of maternal-infant separation.Doughty et al. found that for women with GDM, newborns were less likely to stay with them in their hospital room than women without GDM (aOR 0.55; 95% CI 0.36, 0.85) [47].Risk factors for not initiating or breastfeeding less than 30 days included infants with a health problem or prematurity [46].Morrison et al. [55] describe an association between caesarean birth and the cessation of breastfeeding before 3 months (OR 1.70; 95% CI 1.04, 2.76) [55].Similarly, Chamberlain et al. [44] reported lower breastfeeding rates among women having a preterm infant or caesarean birth [44].Maternal-infant separation following birth was reported to affect breastfeeding, milk supply and bonding as one woman explains: "They let me see him for just a second and then they said that he needed to go to the nursery for monitoring. . .I didn't get him skin to skin for hours" [50] Supplementation with CMF Several papers reported on the use of CMF for women with GDM.Oza-Frank et al. [56] reported an increasing trend of women with a recent history of GDM being offered CMF as a strategy to address any breastfeeding challenges [56].They found women with a recent history of GDM were more likely to introduce commercial milk formula (CMF) within the first two days (79.4%), than women without GDM (53.8%) (P < 0.01; aOR 3.48; 95% CI 1.47, 8.26) [56].Oza-Frank et al. found women with a recent history of GDM were more likely to receive a pump (OR 1.28; 95% CI 1.07, 1.53) and a CMF gift-pack (OR 1.17; 95% CI 1.03, 1.34) compared with women without GDM [57].Women with GDM were more likely to report that their physicians prefer CMF (aOR 2.82; 95% CI 1.17, 6.79) [47].Jagiello and Azulay Chertok reported that the rate of CMF use during hospital stays where there was no medical indication was 68.4% (n = 39) [50].
The indication for the use of CMF was neonatal hypoglycaemia, along with other medical conditions.However, hospital records showed that CMF was given to these infants, even though it was not medically indicated [50].Jagiello and Azulay Chertok found some women felt under supported by their maternity care providers and felt encouraged to supplement with CMF [50]: "The nurses in the hospital insisted on giving formula.Now the baby is not satisfied with breastfeeding and I am not sure that I have enough milk so I start with breastfeeding and then give formula." [50] "I was pretty traumatized at day four when I went to the pediatrician and they threw some formula at me and said . . .put your baby on formula because you're not giving him enough." [50] Education and support Consistent support and advice was described as important to promote breastfeeding.Stuebe et al. found women with a recent history of GDM who received specialised  [50] Women with GDM are more likely to experience delayed contact with their infants and are more likely to be encouraged to supplement with CMF.However, with appropriate and timely education and support, women with GDM can experience successful breastfeeding outcomes.

Maternal factors and family influences
Seven quantitative studies and the qualitative study reported on maternal factors and family influences on breastfeeding [45-47, 49-52, 55].

Maternal factors
Chertok and Sherby found a significantly greater proportion of women with a recent history of GDM reported perceived delayed lactogenesis II compared with women without DM (Fisher's exact test, p = 0.029) [45].Whilst Jagiello and Azulay Chertok revealed that 41% of women in their study reported delayed lactogenesis II and 44% reported perceived insufficient milk supply [50].A perception of insufficient milk supply was described by women as frustrating and feeling as though they were depriving their infant of nourishment [50].Concerns for the infant's health following birth also influenced breastfeeding.Among the infants in their study, 33.3% (n = 9) had experienced complications including hypoglycaemia (14.8%, n = 4) [50].
One large quantitative study [51] retrospectively reported that mothers who were overweight with a history of GDM were as likely to breastfeed as women with GDM without overweight (OR 0.95; 95% CI 0.87, 1.03) [51].However, a lack of specific data on breastfeeding practices reduces confidence in the findings.Similar findings were reported by Haile et al. [49] with no statistical difference found between women who had normal gestational weight gain and women who exceeded the recommended guidelines [49].However, Haile et al. [49] found that women who had gestational weight gain below the Institute of Medicine guidelines, were less likely to exclusively breastfeed in comparison to women who experienced normal gestational weight gain (OR 0.62; 95% CI 0.45, 0.85) [49].
Conversely, two studies found a greater body mass index (BMI) was associated with breastfeeding outcomes that do not meet the well-documented WHO guidelines [59].Morrison et al. found that a higher BMI (2 unit increased) was associated with cessation of breastfeeding at or before 3 months (OR 1.08; 95% CI 1.01, 1.57) [55].Similarly, Laine et al. found women who breastfed for less than 6 months had a higher pre-pregnancy BMI than women who breastfed for 6 months or longer (P < 0.001 for linearity) [52].Cordero et al. also reported that being overweight or severely obese increased the likelihood of not breastfeeding at 30 days.This finding was associated with smoking during pregnancy and having a caesarean section [46].

Family influences
Morrison et al. found that breastfeeding problems at home was association with cessation of breastfeeding at or before 3 months (aOR 8.01; 95% CI 4.57, 14.05); returning to work within the first three months (OR 3.39; 95% CI 1.53, 7.55), and women experiencing inadequate breastfeeding support (OR 1.88; 95% CI 1.10, 3.22) [55].However, Morrison et al. reported being in a de facto relationship or married was a protective factor against the early cessation of breastfeeding (OR 0.14; 95% CI 0.03, 0.62) [55].Partner, family, and friend support were cited as supportive resources [50]: "My husband's awesome . . .he's like, [you should breastfeed] because it's healthier for him and it's healthier for you." [50] Jagiello and Azulay Chertok found some women were encouraged to terminate breastfeeding and/or supplement with formula following breastfeeding challenges such as delayed lactogenesis or decreased milk supply [50].
"and people are . . .like you should just stop, you should just pump, you should just use formula, why are you doing this?" [50] Women with GDM are more likely to experience delayed lactogenesis II or perceived insufficient milk supply and more likely to experience breastfeeding challenges than women without GDM.However, breastfeeding success can be enhanced in women with a supportive network and encouragement.

Determinants of health
It appears that there are several determinants of health influencing breastfeeding outcomes and creating an added barrier for women with a history of GDM [43,44,46,52,55].
There is an association between ethnicity and breastfeeding outcomes.Chamberlain et al. [44] found lower breastfeeding rates among women who were Indigenous (53%) compared with women who were not (60%) (OR 0.78; 95% CI 0.70, 0.88, P < 0.0001) [44].Baerug et al. [43] found women who were of South Asian ethnicity ceased predominant breastfeeding earlier than women of Western European ethnicity (aHR 1.53; 95% CI 1.04, 2.25) [43].There also appears to be an association between socioeconomic status and breastfeeding outcomes with Morrison et al. [55] finding that cessation of breastfeeding at three months or earlier was increased in women of low socioeconomic status (SEIFA 1 unit increase) (OR 0.89; 95% CI 0.81, 0.97) [55].More broadly, Laine et al. [52] found women who breastfed for less than six months were more likely to be younger, less well educated, or smokers, than women who breastfed for six months or longer (P < 0.001 for linearity) [52].Cordero et al. [46] also found several factors associated with breastfeeding initiation failure, including lower education, obesity, smoking, and in their study, African American ethnicity [46].The findings recognise that determinants of health may impact breastfeeding for all women however most authors suggest that women with added vulnerabilities experience additional barriers.

Discussion
This review investigated the breastfeeding experiences and outcomes of women in high-income health care contexts when there was a history of GDM in the corresponding pregnancy.It was anticipated that the experiences and outcomes reported in the studies could reveal factors influencing breastfeeding or breastmilk feeding in women with GDM.This review found that there were differences in breastfeeding outcomes between women with GDM and women without GDM.Maternity care practices, maternal factors and family influences, as well as underlying determinants of health contributed to lower rates of breastfeeding in women with GDM.
There are multiple factors influencing the intention, initiation, and duration of breastfeeding amongst all women, regardless of GDM status.However, this review finds women with a recent history of GDM are even less likely to breastfeed than women without GDM or were even more likely to cease breastfeeding earlier than women without GDM.These results may be partially explained by the increased risk of pregnancy and birth complications for women with a recent history of GDM [31,32].For example, a recent prospective cohort study of 378 women with GDM during their pregnancy reported a statistically significant increase in the incidence of shoulder dystocia and caesarean section birth, as well as an increased probability of foetal distress and preterm infants [60].Intrapartum interventions are known to contribute to maternal exhaustion, infant metabolic maladaptation and/or separation with supplementation and less favourable breastfeeding outcomes [61], even without the added complexity of GDM and unsupportive hospital clinical practice guidelines.It is well documented that injudicious interference with the normal physiology of lactogenesis will delay its onset.
Maternal factors and family influences as well as determinants of health also influence breastfeeding outcomes, a common finding across different highincome nations in this review.For example, women with a history of GDM who had reported increased rates of partner and family support for the initiation and continuation of breastfeeding, had greater odds of reporting breastfeeding initiation and exclusive breastfeeding [62][63][64][65].This finding shows there is a clear relationship between the two concepts.A 2018 review of effective strategies to support breastfeeding indicated support and education strategies or interventions may improve breastfeeding practices, particularly if involving other family members such as the women's mother or spouse [59].The same review found additional supports were required for women with known medical complexities, in vulnerable or marginalised populations, and lower socio-economic status.Our review shows that women with a history of GDM may have medical and social complexities that further heighten their risk of not breastfeeding, intensifying the need for additional supports.Knowing that longer and more exclusive breastfeeding is known to be a protective factor for developing T2DM in the long term [66], antenatal and postnatal education needs to target the woman's immediate family on the supportive measures that can be undertaken to improve the potential for breastfeeding success and further reduce the potential for adverse health outcomes.
It was found that maternity care practices influence breastfeeding in women with a recent history of GDM at all stages of the breastfeeding journey.Health professionals need to provide evidence-based breastfeeding support that is sensitive and tailored to the woman's unique needs [67].Our review affirms this practice, for example finding that women with an immediate history of GDM demonstrated better breastfeeding outcomes with support and the use of a lactation consultant [48,50,58].In contrast, our findings also showed this group were more likely to be exposed to non-evidence-based practices such as being given breast pumps and encouraged to use CMF [50,56,57], disrupting the women's sense of confidence in her ability to breastfeed successfully, also known as breastfeeding self-efficacy, which is an important predictor of initiation and the duration of breastfeeding [68,69].The development of breastfeeding self-efficacy is most vulnerable during late pregnancy and during the first week postpartum, being highly susceptible to the type of experiences encountered [68].Our review shows that women with a history of GDM are more likely to encounter negative breastfeeding experiences than those without this condition, hampering their self-efficacy development and impacting their breastfeeding practices [50,56,57].Maternity care practices that increase the probability of early successful experiences are crucial to implement in this group as a further protective measure against the known long-term impacts [2,12,24,25,27].
At multiple levels of society the call to create an environment that produces polices and practice guidelines free from commercial influence and protecting the rights of all women to make infant feeding decisions that meet their goals is getting stronger [70].In a metaanalysis of the outcomes for the Baby Friendly Hospital Initiative (BFHI), several interventions were recommended to enhance breastfeeding outcomes.Rollins et al. [71] reported increased rates of exclusive breastfeeding (49%) and increased rates of any breastfeeding (66%) when BFHI breastfeeding support interventions were implemented.These interventions, as outlined in the Ten Steps to Successful Breastfeeding include early skin-to-skin contact and breastfeeding support, protection of lactation if mothers are separated from their infant, offering breastmilk substitutes only where there are clearly defined medical reasons, rooming-in and ongoing community support [72,73].The incorporation of BFHI recommendations into hospital guidelines as a routine set of practices in many high-income nations is needed [72], and when evidence-based breastfeeding support is not utilised, barriers to breastfeeding success are created [74].Such advocacy is warranted for all women.Our findings suggest that women with a history of GDM could benefit from supports to enhance breastfeeding, and that widespread implementation of the BFHI package of interventions would present as modifiable opportunities.

Recommendations for policy and practice
Recommendations for the enhanced support of the breastfeeding initiation and duration for women with a recent history of GDM have been drawn from the findings discussed above, namely: 1. Implement the full package of BFHI interventions 2. Specifically tailor antenatal and postnatal breastfeeding support to the individual needs of women diagnosed with GDM during their pregnancy 3. Involve the woman's partner and family in the initiation and support of breastfeeding While these recommendations are applicable to all women, the known challenges faced by women with GDM that impact breastfeeding need to be acknowledged and accounted for in management plans to mitigate risk factors.

Strengths and limitations
This systematic integrative review is the first of its kind to examine and synthesise the experiences and outcomes of breastfeeding in women with a history of GDM in high-income settings, providing insights into the positive and negative influences on breastfeeding for women in this context.Being solely focussed on GDM rather than a combination of GDM, T1DM and T2DM adds strength and confidence to the findings.The papers included in this review were high quality with a range of CCAT scores between 68.75% and 87.5%.The range of high-income nations from which the studies originated increases the ability to generalise the findings to the Australian context because similar maternity care systems, as well as GDM screening and diagnostic processes may be used.
A limitation of this review was the lack of diversity amongst the study designs included.Most included papers used a quantitative study design, limiting our understanding of women's experiences of breastfeeding following a GDM pregnancy.It is recognised that by not including low-and middle-income nations, some important research findings may have been missed.Another limitation is that studies included in the review did not uniformly control for variables which are likely to affect the initiation and duration of breastfeeding, regardless of status, for example, mode of birth, prior breastfeeding experience, smoking, obesity, socio-economic status, educational status, GDM treated with diet or medication, birth in a baby-friendly hospital.Further limitations identified in each study are listed in Table 2 and include a lack of operational definitions of breastfeeding, loss of follow up past 6 weeks and 6 months postpartum, differences in the way data was collected during the study period, and variation of breastfeeding practices between healthcare facilities.

Further research
This review highlights a paucity of existing research related to women's experiences of breastfeeding with a history of GDM.Future research should aim to understand the experiences of breastfeeding mothers with a history of GDM, not only in high-income contexts but in low-and middle-income.Understanding the woman's experience will generate additional information, which when combined with the quantitative findings of this review, will be highly beneficial for improving maternity breastfeeding practices for both this cohort of women, and all breastfeeding women.

Conclusion
This integrative review found the rates of initiation and duration of breastfeeding, were lower amongst women with a history of GDM when compared to their non GDM counterparts.Maternity care practices, such as those recommended by the BFHI, are particularly important in facilitating breastfeeding for mothers with a recent history of GDM.Maternal factors and family influences identified amongst the cohorts, can act as both facilitators and barriers to breastfeeding.Underlying social determinants of health including socioeconomic status appear to have a greater effect on women with a history of GDM than the wider birthing population.Appropriate, evidencebased, and timely professional support is key to a positive breastfeeding experience for all women with a recent history of GDM.Breastfeeding education and support need to encompass the individual needs of women with GDM and should include the immediate and extended family as they are major sources of influence.Well prepared, and supported women will have the ability to handle any challenges in achieving their infant feeding goals.

Table 1
Sample search terms using the SPIDER framework

Table 2
Crowe Critical Appraisal Tool (CCAT) scores outlining the quality appraisal of included papers

Table 3
Summary of included studies women without a history of GDM breastfed early in the first half hour following birth, compared to women with a history of GDM (p = 0.016) • aHR 1.33, 95% CI, 1.01-1.77,p<0.05Breastfeeding initiated by 99% of mother's both with and without a history of GDM.Breastfeeding rates during the postpartum period:• End of week 1 postpartum: 86% of mothers with a history of GDM, versus, 91% of mothers without a history of GDM (p = 0.07) • End of week 2 postpartum: 78% of mothers with a history of GDM, versus, 88% of mothers without a history of GDM (p < 0.01) End of week 12 postpartum: 56% of mothers with a history of GDM, versus, 67% of mothers without a history of GDM (p = 0.02) • OR 0.32, 95% CI 0.27-0.38,p<0.0001 â rates of breastfeeding amongst Indigenous Australian women with a history of GDM compared with non-Indigenous women with a history of GDM • OR 0.78, 95% CI 0.70-0.88),≤0.0001)•Mothers with a history of GDM: 29%• Mothers without a history of GDM: 58.8% á proportion of women with a history of GDM reported perceived delayed lactogenesis II compared with women without a history of GDM Fischer's exact test, p = 0.029